I have Win 7 and I have ‘rustc’ , ‘cargo’ , ‘rustup’ in the PATH and I can access all three in the terminal. Do I still need to have rustup actually download and install the rust language so I can I create rust source files ?

You will need rustup to update Rust, switch toolchains (stable, beta, nightly, and different versions of the compiler) and to install other targets painlessly. But otherwise, not really. I would still keep it around so that you can update Rust and swap toolchains.